Cable conveying system.



IE. B. SHIELDS & L. L. TYLER.

v CABLE CONVEYING SYSTEM.

APPLICATION FILED APR. 7, I914.

Patented Feb. 1., 1916.

m t m h THE COLUMBIA PLAIjoGRAPH co.. WASHINGTON, D. c.

r'r seine.

EDWARD IB. SHIELDS AND LEWIS L. TYLER, 0F TACOMA, WASHINGTON.

CABLE CONVEYING SYSTEM.

Application filed April 7, 1914.

To all whom it may concern:

Be it known that we, EDWARD B. SHIELDS and Lnwrs L. TYLER, citizens of the United States, and residents of Tacoma, in the county of Pierce, State of Washington, have invented certain new and useful Improvements in Cable Conveying Systems, of which the following is a specification.

This invention relates to mechanism for conveying logs and other objects over rough land, by means of cables. It is especially designed for that class in which a single endless cable is used for supporting and transporting the loads.

The objects of the invention are to provide automatic means for preventing the tension in the cable from exceeding any predetermined amount, and means for compensating for variations in the loads and in the lengths in the spans between supports.

The invention further lies in the devices, mechanisms, and arrangements for carrying out the said objects.

This invention is illustrated in the accompanying drawings, in which Figure 1 is a general perspective View of our invention in use; Fig. 2 is a plan ofthe driving or receiving end of the system; Fig. 3 is a side elevation of the tension governor, a portion being broken away to reveal the interior; and Fig. 4 is a cross-section thereof.

Similar numerals of reference refer to similar parts throughout the several iews.

Our invention is especially worked out for logging operations in a rough country, but can be equally'well applied to various other circumstances and uses, especially if the loads being transported vary from time to time. Those portions of the apparatus relating to the supporting sheaves between the ends of the line, and to the connections between the loads and the cable, are not illustrated in detail and are not claimed in this application.

Referring to the drawings, it will be seen that the endless cable 1 is stretched between the ends of the line, one side only being supported by the sheaves 2. The sheaves 2 are spaced as nearly equidistant as is convenient and are preferably supported in fixed positions by means of cables stretched between trees, towers, or other elevated objects. The return side of the cable 1 may be run on the ground or may be supported at intervals in any desired manner. At the outer or sending end of the system, the

Specification of Letters Patent.

Patented Feb. 1, 1916.

Serial No. 830,105.

cable 1 is passed around a large sheave 3, whose position is adjustable by means of pulleys and tackle by which it is attached to its anchorage, whereby any differences in the length of the cable, due to stretching or' other causes, may be compensated so that they will not affect the inner or receiving end of the system. At the receiving end of the system, the cable 1 is led through suitable guide pulleys to, and several times around, a driving drum d, and thence around the floating sheave 5 and thence returns to the sending end.

The drum 4: is driven by the engine 6 (preferably reversible) and is securely anchored against movement. The drum 4 is sufliciently large to allow the cable 1 to pass below the frame or platform on which it is mounted both as it approaches the drum and as it passes therefrom to the floating sheave 5. The floating sheave 5 is mounted on a car 7, which travels freely on the rails 8. The tension of the cable 1 tends to draw the car 7 toward the center of the system and this action is opposed by the following described automatic tension governor and'apparatus: An engine 9 is fixedly mounted on a suitably anchored frame and acts on a drum 10, always tending to wind the end of the cable 11 on the said drum. The engine is supplied with live steam from a boiler 12, the said steam passing through a suitable reducing valve 13 between the boiler and the engine. The pressure of the steam in the engine is augmented or reduced by the automatic manipulation of the said reducing valve 13 by means of the tension governor, hence the steam engine will wind the cable 11 on the drum 10 when the pressure in the engine is suliicient to overcome the tension in the cable 11, or the cable 11 will unwind from off said drum 10 when its tension overcomes the pressure of the steam in the engine. As above stated, one-end of the cable 11 is secured to the drum 10. The cable 11 extends from the drum 10, around one of the pulleys in the fixed block 1-1, to and around the pulley block 15, which is secured to the car 7, and then back and around another pulley in the block 14, and thus to the tension governor to which its other end is secured. The cable may be passed several times around the pulleys in the blocks 14 and 15 if desired, so long as one end is secured to the drum 10 and the other end to the tension governor. The tension governor comprises two straps 16 and 17 with compression springs 18 mounted between them. The strap 16 is secured to the frame on which the engine 9 and drum 1.0 are mounted, while the end of the cable 11 is attached to the strap 17. The tension in the cable compresses the springs 18 between the straps 16 and 17. A bell-crank lever 19 is mounted on a pivot pin 20, which is carried on a pair of brackets 21 formed on the strap 16. One end of the bell-crank lever 19 is connected to the strap 17 in a suitable manner. The other end of the bell-crank lever 19 is connected by suitable rods 22 to the reducing valve 13. lVhen the tension in the cable 11 changes, the springs 18 will cause the straps 16 and 17 to move relatively to each other, and this motion will turn the bell-crank lever 19 on its pivot 20 in such a manner as to actuate the valve 13 to reduce the pressure in the steam engine 9 when the tension in the cable 11 exceeds the normal predetermined amount, and, correspondingly, to increase the said pressure when the tension is less than the said predetermined amount.

A lever 23 is mounted at the end of the track adjacent the block 14:, in such position as to be engaged by the car 7 thereon, when it reaches its extreme position on the track. This lever is connected by rods, or otherwise, to the valve in the steam pipe of the main driving engine, so that when the car engages the lever the cable 1 will-be stopped and then the adjustment of the sheave 3 may be tightened to draw thesaid car out on the track.

Our invention operates in the following manner :A log is attached to the cable 1 at the sending end and the cable is started by operating the engine 6, thus drawing the log toward the receiving end. At this time, since there is only a partial load on the system, practically all the slack provided for is taken up by the floating sheave 5 on the car 7 which is pulled near the extreme end of its travel by the cable 11 which is wound around the drum 10 to practically its full extent. As the load passes beyond the first sheave 2 a second log is attached to the cable 1 and therefore the condition of tension and slack in the cable changes. The strain on the cable 1, due to the logs suspended between the supporting sheaves 2, will depend on the weight of the logs, the distance between said supporting sheaves, and the sag in the cable between the said sheaves, and this strain is transferred to the floating sheave 5 and thus to the cable' 11 where,'as' before described, an increase in said strain will allow the cable 11 to be paid off the said drum 10 and thus increase the available slack and thus keep the strain within the required bounds. Since the logs will vary in weight and the spans between the supporting sheaves will also vary, it is evident that the sag needed by one log will vary each time it passes to a new span, and since all the logs are secured to the same cable they will transfer the excess sag of one to'supply the need-ed sag of another and thus they will automatically compensate for variations between the loads and spans and the floating sheave will only be called on to supply suflicient slack for the entire system and to preserve the total strain in the cable at a point near the predetermined amount.

Having described our invention, what we claim is:

In an apparatus of the class described, the combination with an endless supporting and transporting cable extending between two terminals, one of said terminals being fixed and the other being adapted to be moved; intermediate means between. said terminals supporting one side only of said endless cable, said cable moving freely longitudi nally over said supporting means and sagging between adjacent supports in accordance with the load thereon, the distance between the supports, and the strain in the cable; pulling means engaging and actuating said cable between the last said support and said movable terminal; means engaging I the movable terminal and applyinga forcethereto opposed to the strain of s'aidendless cable whereby its position is governed; and meansfor varying the force of said moving means whereby the force is increased as the strain. in the cable is decreased and is de creased as the strain in the cable is increased.

EDWARD B. SHIELDS.

Copies of this patent may be obtained f r five cents each, by addressing the Commissioner of Patents,

' Washington, 13.6. 

